[cisco-voip] 7960 PC port

[Jonathan Charles]

Everything from QoS not working, to getting the wrong DHCP IP, to not
routing calls to the right VLAN, to the PC port data getting routed
incorrectly...

The reason for all of this is a core component of the design and
interraction between the switches and the phones.

As you know, the phones and switch use CDP to negotiate a Dot1Q trunk
between them, if the switch is nailed down as a trunk, this
negotiation process gets all wonky.

Will the phones still work? Possibly... I have seen them work, but I
have also seen them not.

The biggest issue comes does to switch QoS, which does not work with
the nailed-in trunk.




Jonathan



On 3/31/06, Bell, Joe <Joe_Bell at adp.com> wrote:
>
> This config:
>
> interface FastEthernet5/1
> switchport mode trunk
> switchport trunk encapsulation dot1q
> switchport trunk native vlan 10
> switchport voice vlan 110
> spanning-tree portfast
>
> ...is straight out of the doc's.  I have copied this text from the CCIE
> Voice tutorial given at Networkers last year by Ben Ng, who is one of
> the test designers and proctors.  Maybe he is wrong though.  This
> certainly is the "older" model for setting up switch ports as the newer
> switch models that you have quoted have a new command structure, but
> this still works.  What kind of inconsistency have you seen?  This
> config works for me every time and I have never seen any goofy behavior.
>
> I would be interested to hear from anyone who has had an issue with this
> command set for voice ports.
>
>
> -----Original Message-----
> From: cisco-voip-bounces at puck.nether.net
> [mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Jonathan
> Charles
> Sent: Friday, March 31, 2006 8:08 AM
> To: Rupp Christian
> Cc: cisco-voip at puck.nether.net
> Subject: Re: [cisco-voip] 7960 PC port
>
> Wow.
>
> This is kind of surprising that so many voip engineers are making this
> mistake.
>
> The voice vlan is NOT supported (and does not work correctly) on ports
> configured as trunks.
>
> For the 3560:
> http://www.cisco.com/univercd/cc/td/doc/product/lan/cat3560/12225see/scg
> /swvoip.htm
> "Voice VLAN is only supported on access ports and not on trunk ports,
> even though the configuration is allowed."
>
> For the 3750:
> http://www.cisco.com/univercd/cc/td/doc/product/lan/cat3750/12225see/scg
> /swvoip.htm
> "Voice VLAN is only supported on access ports and not on trunk ports,
> even though the configuration is allowed."
>
> While you may have gotten it to work, it is not consistent...
>
>
>
> Jonathan
>
> On 3/31/06, Rupp Christian <Christian.Rupp at etavis.ch> wrote:
> > Hi Peter!
> >
> > We use this configuration that works:
> >
> > interface FastEthernet0/3
> >  switchport trunk encapsulation dot1q
> >  switchport trunk native vlan yy
> >  switchport voice vlan xx
> > !
> >
> > Is the DHCP Server for the voice vlan the same like the PC vlan?
> > Maybe you have to configure a helper-address?
> >
> > Regards,
> > Christian
> >
> > _______________________________________________
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> > cisco-voip at puck.nether.net
> > https://puck.nether.net/mailman/listinfo/cisco-voip
> >
>
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